Raid 0 does give you a performance boost as it splits your data into two equal segments and writes each one to a different hard drive ( this is based on a two hard drive raid 0 )
doing this improves read/write times over a single hard drive.
basically a raid 0 will combine the 2 drives to show up as 1 single drive with a combined storage, EG: 2X 250G drives will show as a 500G, 3X250G as 750G, ect ( less after formatting ).
Ideally you would want to get 2 or more smaller drives of the same model so for example look at maybe getting 3X 80G drives to obtain a 240G raid 0 array as 3 drives will increase performance over 2. You can then use your 320G drive as a backup drive and keep an image or clone of your array on that in case your array fails. If a raid 0 array fails there is very little hope of retrieving your information, hence the backup
Yes you can do it but you really need two or more identical hard drives for optimal performance or you are taking away from the concept of in creasing performance.
